An article processing charge (APC), also known as a publication fee, is a fee which is sometimes charged to authors. Most commonly, it is involved in making an academic work available as open access (OA), in either a full OA journal or in a hybrid journal.[1][2][3] This fee may be paid by the author, the author's institution, or their research funder.[4] Sometimes, publication fees are also involved in traditional journals or for paywalled content.[5] Some publishers waive the fee in cases of hardship or geographic location, but this is not a widespread practice.[6] An article processing charge does not guarantee that the author retains copyright to the work, or that it will be made available under a Creative Commons license.